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Peanut Allergy

Topic Overview

What is a peanut allergy?

A peanut allergy is a
reaction that occurs when your body mistakenly identifies peanuts as harmful
substances. When you eat peanuts or food containing peanuts, your
immune system—the body's natural defense system that
fights infections and diseases—overreacts and can cause a serious, even
life-threatening response.

What causes a peanut allergy?

An
allergic reaction occurs when your immune system
overreacts and releases chemicals, including histamine, into your blood. These
chemicals can affect different tissues in the body, such as the skin, eyes,
nose, airways, intestinal tract, lungs, and blood vessels. It's not clear why
peanuts trigger this response in some people.

What are the symptoms?

Symptoms of peanut allergy
can range from mild to severe. If you have a mild reaction, you may
get a stomachache, a runny nose, itchy eyes,
hives, or tingling in your lips or tongue. If your
reaction is worse, you may develop additional symptoms such as a tight throat,
hoarse voice, wheezing, coughing, and/or feeling sick to your stomach. Your symptoms may start from within a few minutes to a few
hours after eating peanuts or peanut products.

People who are
allergic to peanuts may have a life-threatening reaction called
anaphylaxis. Symptoms of anaphylaxis can include
problems breathing and swallowing; vomiting and diarrhea; dizziness;
dangerously low blood pressure; swelling of the lips, tongue, throat, and other
parts of the body; and loss of consciousness. If not treated, death can result.
Anaphylaxis usually occurs within minutes but can occur up to several hours
after eating peanuts or peanut products.

How is a peanut allergy diagnosed?

To diagnose a
peanut allergy, your doctor will start with a
medical history and a physical exam. Your doctor will
ask about any family food allergies, especially siblings with peanut allergies. He or she will ask detailed questions
about your symptoms, how soon your symptoms began after you ate the food, and if any over-the-counter allergy medicines like an antihistamine were helpful. Your doctor will ask if other people also got sick, how the food was prepared, and what other foods were eaten.

It's important to find out whether you have a
food allergy or food intolerance. Your doctor may ask you to keep a record of
all the foods you eat and any reactions to the foods. Your doctor will also consider if your reaction could have been caused by things like allergies to medicines or insect stings, food poisoning, irritants in foods, and exposure to skin irritants.

Your doctor may ask you
to try an elimination diet, an oral food allergy challenge, or both.

In an elimination diet, you avoid eating foods that may be causing an allergic reaction and see if your symptoms go away. If symptoms come back when you eat the food again, your doctor can confirm your food allergy. The elimination diet can last from 2 to 8 weeks.

In an oral food allergy challenge, you eat a variety of foods that may or may not cause an allergic reaction. Your doctor
watches to see if and when a reaction occurs. This test
is considered the best way to diagnose a food allergy.

You may also have
allergy tests, such as skin tests or blood tests, to determine what foods you are allergic to after you have been diagnosed with having a food allergy.

How is it treated?

If you accidentally eat a
peanut, follow your doctor's instructions. For a mild reaction, you may only
need to take an
antihistamine, such as diphenhydramine hydrochloride
(Benadryl), to reduce your symptoms of a runny nose or itchy skin.

If your allergic reaction is more severe, follow the anaphylaxis action plan from your doctor for this type of reaction. If you have had a severe reaction
previously, your doctor has probably prescribed a medicine called
epinephrine. Give yourself the epinephrine shot, and call 911 for further
instructions.

Even if you feel better after giving yourself the shot,
symptoms of anaphylaxis can recur or suddenly appear hours later. You need to
be observed in a hospital for several hours after your symptoms go away.

If you do not have epinephrine and are having a severe allergic
reaction, call 911 immediately.

How can I avoid an allergic reaction?

To prevent
an allergic reaction to peanuts:

Understand your allergy and know that you
need to protect yourself. Read food labels or ask kitchen staff at restaurants
if there are peanuts or peanut oils hidden in any of the foods you order. For
example, some cooks thicken chili with peanut butter.

Some people are so severely allergic to
peanuts that being near them or breathing air that contains peanut residue can
cause an allergic reaction.

Let others know that you or your child
has a peanut allergy. Make sure that all caregivers (such as school
administrators, teachers, babysitters, and coaches), friends, and coworkers:

Know what the symptoms of an allergic
reaction look like.

Know where the epinephrine shot is kept and how
to give the shot.

Have a plan to transport you or your child to the
hospital.

Wear a
medical alert bracelet or medallion that lists your peanut allergy. This will
alert emergency response workers if you have a severe allergic reaction.
Medical alert jewelry can be ordered through most pharmacies or on the
Internet.

Keep your epinephrine shot with you at all times. Make
sure older children know how to give you or themselves the shot. Talk with your
doctor or pharmacist if you are unsure how to give yourself the
shot.

Keep other medicines such as antihistamines with you for mild reactions if your doctor recommends it. Antihistamines are not a substitute for epinephrine in a severe allergic reaction.

If you think you are having an allergic reaction:

Get help. Do not minimize the seriousness of the
problem.

After you give yourself an epinephrine shot, call your
doctor immediately or seek other emergency services. You will need to be
observed for several hours to make sure the reaction does not recur.

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